1# serial 10
2# See if we need to provide symlinkat replacement.
3
4dnl Copyright (C) 2009-2021 Free Software Foundation, Inc.
5dnl This file is free software; the Free Software Foundation
6dnl gives unlimited permission to copy and/or distribute it,
7dnl with or without modifications, as long as this notice is preserved.
8
9# Written by Eric Blake.
10
11AC_DEFUN([gl_FUNC_SYMLINKAT],
12[
13  AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
14  AC_REQUIRE([gl_FUNC_OPENAT])
15  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
16  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
17  AC_CHECK_FUNCS_ONCE([symlinkat])
18  if test $ac_cv_func_symlinkat = no; then
19    HAVE_SYMLINKAT=0
20  else
21    AC_CACHE_CHECK([whether symlinkat handles trailing slash correctly],
22      [gl_cv_func_symlinkat_works],
23      [AC_RUN_IFELSE(
24         [AC_LANG_PROGRAM(
25           [[#include <fcntl.h>
26             #include <unistd.h>
27           ]],
28           [[int result = 0;
29             if (!symlinkat ("a", AT_FDCWD, "conftest.link/"))
30               result |= 1;
31             if (symlinkat ("conftest.f", AT_FDCWD, "conftest.lnk2"))
32               result |= 2;
33             else if (!symlinkat ("a", AT_FDCWD, "conftest.lnk2/"))
34               result |= 4;
35             return result;
36           ]])],
37         [gl_cv_func_symlinkat_works=yes],
38         [gl_cv_func_symlinkat_works=no],
39         [case "$host_os" in
40                             # Guess yes on Linux systems.
41            linux-* | linux) gl_cv_func_symlinkat_works="guessing yes" ;;
42                             # Guess yes on glibc systems.
43            *-gnu* | gnu*)   gl_cv_func_symlinkat_works="guessing yes" ;;
44                             # If we don't know, obey --enable-cross-guesses.
45            *)               gl_cv_func_symlinkat_works="$gl_cross_guess_normal" ;;
46          esac
47         ])
48      rm -f conftest.f conftest.link conftest.lnk2])
49    case "$gl_cv_func_symlinkat_works" in
50      *yes) ;;
51      *)
52        REPLACE_SYMLINKAT=1
53        ;;
54    esac
55  fi
56])
57